Methods for forming semiconductor constructions, and methods for selectively etching silicon nitride relative to conductive material

ABSTRACT

The invention includes methods for selectively etching insulative material supports relative to conductive material. The invention can include methods for selectively etching silicon nitride relative to metal nitride. The metal nitride can be in the form of containers over a semiconductor substrate, with such containers having upwardly-extending openings with lateral widths of less than or equal to about 4000 angstroms; and the silicon nitride can be in the form of a layer extending between the containers. The selective etching can comprise exposure of at least some of the silicon nitride and the containers to Cl 2  to remove the exposed silicon nitride, while not removing at least the majority of the metal nitride from the containers. In subsequent processing, the containers can be incorporated into capacitors.

RELATED PATENT DATA

This patent resulted from a divisional of U.S. patent application Ser.No. 12/652,955, which was filed Jan. 6, 2010, and which is herebyincorporated herein by reference; which resulted from a divisional ofU.S. patent application Ser. No. 11/506,347, which was filed Aug. 17,2006, which issued as U.S. Pat. No. 7,666,797, and which is herebyincorporated herein by reference.

TECHNICAL FIELD

The invention pertains to methods of forming semiconductorconstructions, and in particular aspects pertains to methods forselectively etching one material relative to another; such as, forexample, selectively etching silicon nitride relative to conductivematerial.

BACKGROUND OF THE INVENTION

Numerous applications are known in which it is desired to selectivelyetch one material relative to another. For instance, it is frequentlydesired to selectively etch silicon nitride relative to metal nitride(with exemplary metal nitride being titanium nitride, tantalum nitride,hafnium nitride, aluminum nitride, etc.). For purposes of interpretingthis disclosure and the claims that follow, an etch is considered to beselective for a first material relative to a second material if the etchremoves the first material at a faster rate than the second material,which can include, but is not limited to, etches which are 100%selective for the first material relative to the second material.

Among the applications in which it can be desired to selectively etchsilicon nitride relative to metal nitride are applications in whichsilicon nitride lattices are patterned to support metalnitride-comprising capacitor containers, such as, for example,processing analogous to that described in United States PatentApplication Publication number 2005/0054159.

It is desired to develop new methods for utilizing lattices to supportcapacitor storage nodes. It is further desired to develop new methodsfor selectively etching silicon nitride relative to conductive material,and it would be particularly desirable for such methods to be applicableto processes in which silicon nitride lattices are patterned to supportcapacitor containers. It is further desirable to develop new methods forselectively etching one material relative to another.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention are described below withreference to the following accompanying drawings.

FIG. 1 is a diagrammatic, fragmentary, cross-sectional view of asemiconductor construction at a preliminary processing stage of anexemplary aspect of the present invention.

FIG. 2 is a view of the FIG. 1 fragment shown at a processing stagesubsequent to that of FIG. 1.

FIG. 3 is a view of the FIG. 1 fragment shown at a processing stagesubsequent to that of FIG. 2.

FIG. 4 is a view of the FIG. 1 fragment shown at a processing stagesubsequent to that of FIG. 3.

FIG. 5 is a view of the FIG. 1 fragment shown at a processing stagesubsequent to that of FIG. 4.

FIG. 6 is a view of the FIG. 1 fragment shown at a processing stagesubsequent to that of FIG. 5.

FIG. 7 is a diagrammatic, fragmentary, cross-sectional view of asemiconductor construction at a processing stage similar to that of FIG.6 in accordance with another aspect of the invention.

FIG. 8 is a diagrammatic, fragmentary, cross-sectional view of asemiconductor construction at a preliminary processing stage of yetanother exemplary aspect of the present invention.

FIG. 9 is a view of the FIG. 8 fragment shown at a processing stagesubsequent to that of FIG. 8.

FIG. 10 is a view of the FIG. 8 fragment shown at a processing stagesubsequent to that of FIG. 9.

FIG. 11 is a view of the FIG. 8 fragment shown at a processing stagesubsequent to that of FIG. 10.

FIG. 12 is a view of the FIG. 8 fragment shown at a processing stagesubsequent to that of FIG. 11.

FIG. 13 is a diagrammatic, fragmentary, cross-sectional view of asemiconductor construction at a preliminary processing stage of yetanother exemplary aspect of the present invention.

FIG. 14 is a view of the FIG. 13 fragment shown at a processing stagesubsequent to that of FIG. 13.

FIG. 15 is a view of the FIG. 13 fragment shown at a processing stagesubsequent to that of FIG. 14.

FIG. 16 is a view of the FIG. 13 fragment shown at a processing stagesubsequent to that of FIG. 15.

FIG. 17 is a view of the FIG. 13 fragment shown at a processing stagesubsequent to that of FIG. 16.

FIG. 18 is a diagrammatic, fragmentary, cross-sectional view of asemiconductor construction at a preliminary processing stage of yetanother exemplary aspect of the present invention.

FIG. 19 is a view of the FIG. 18 fragment shown at a processing stagesubsequent to that of FIG. 19.

FIG. 20 is a diagrammatic, fragmentary, cross-sectional view of asemiconductor construction at a preliminary processing stage of yetanother exemplary aspect of the present invention.

FIG. 21 is a view of the FIG. 20 fragment shown at a processing stagesubsequent to that of FIG. 20.

FIG. 22 is a view of the FIG. 20 fragment shown at a processing stagesubsequent to that of FIG. 21.

FIG. 23 is a diagrammatic, fragmentary, cross-sectional view of asemiconductor construction at a preliminary processing stage of yetanother exemplary aspect of the present invention.

FIG. 24 is a view of the FIG. 23 fragment shown at a processing stagesubsequent to that of FIG. 23.

FIG. 25 is a view of the FIG. 23 fragment shown at a processing stagesubsequent to that of FIG. 24.

FIG. 26 is a diagrammatic view of a computer illustrating an exemplaryapplication of the present invention.

FIG. 27 is a block diagram showing particular features of themotherboard of the FIG. 26 computer.

FIG. 28 is a high level block diagram of an electronic system accordingto an exemplary aspect of the present invention.

FIG. 29 is a simplified block diagram of an exemplary memory deviceaccording to an aspect of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

This disclosure of the invention is submitted in furtherance of theconstitutional purposes of the U.S. Patent Laws “to promote the progressof science and useful arts” (Article 1, Section 8).

The invention includes new methods for selectively etching one materialrelative to another.

In some aspects, the invention includes new methods for selectivelyetching silicon nitride relative to conductive material, and inparticular aspects the invention utilizes a combination of geometry andetch chemistry to accomplish such selective etching. Specifically, theconductive material can be formed as containers havingupwardly-extending openings, and the silicon nitride can be formed asone or more layers between the containers. The openings of thecontainers can be of suitable aspect ratio so that the openings are atleast about one micron deep (in some aspects, at least about 5 micronsdeep), and less than or equal to 4000 angstroms in maximum lateralwidth.

The etch chemistry can be chosen so that reactive species suitable foretching the conductive material do not penetrate very deeply into theopenings (which can occur, for example, if the travel distance of thereactive species into the openings is limited by mean free path, orionic activity time), but so that reactive species suitable for etchingsilicon nitride reach one or more of the silicon nitride layers.

Suitable etch chemistry for some aspects of the invention utilizes Cl₂as the primary etchant, and can utilize a relatively high substrate biasduring the etch (such as, for example, a bias of at least about 25watts, at least about 50 watts, or at least about 150 watts, and inparticular aspects the bias can be from about 25 watts to about 500watts). The conductive material can be any of various compositions, andin particular aspects can comprise, consist essentially of, or consistof a metal nitride; such as, for example, one or more of titaniumnitride, tantalum nitride, aluminum nitride, and hafnium nitride. Insome aspects the conductive material can include one or morecompositions selected from suitable metals, metal-containingcompositions (metal nitrides, conductive metal oxides, etc.), andconductively-doped semiconductor materials (such as, for example,conductively-doped silicon).

Exemplary aspects of the invention are described with reference to FIGS.1-29; with FIGS. 1-7 illustrating a first aspect of the invention, FIGS.8-12 illustrating a second aspect of the invention, FIGS. 13-17illustrating a third aspect of the invention, FIGS. 18 and 19illustrating a fourth aspect of the invention, FIGS. 20-22 illustratinga fifth aspect of the invention, FIGS. 23-25 illustrating a sixth aspectof the invention, and FIGS. 26-29 illustrating exemplary systems thatcan be utilized in some applications of the invention.

Referring to FIG. 1, such shows a semiconductor construction 10comprising a semiconductor material base 12 supporting a plurality ofelectrical nodes 14, 16, 18 and 20. In the shown aspect, the nodes areconductively-doped diffusion regions extending within the semiconductormaterial of base 12.

Base 12 can comprise, consist essentially of, or consist of, forexample, monocrystalline silicon lightly-doped with background p-typedopant, and can be referred to as a semiconductor substrate. To aid ininterpretation of the claims that follow, the terms “semiconductivesubstrate” and “semiconductor substrate” are defined to mean anyconstruction comprising semiconductive material, including, but notlimited to, bulk semiconductive materials such as a semiconductive wafer(either alone or in assemblies comprising other materials thereon), andsemiconductive material layers (either alone or in assemblies comprisingother materials). The term “substrate” refers to any supportingstructure, including, but not limited to, the semiconductive substratesdescribed above.

The conductively-doped diffusion regions can correspond to either n-typedoped regions or p-type doped regions. Although the regions are shown asbeing conductively-doped at the processing stage of FIG. 1, it is to beunderstood that the regions could, in some aspects, be doped at aprocessing stage subsequent to that of FIG. 1. Accordingly, the shownconductively-doped regions can, in some aspects, correspond to locationsfor conductively-doped regions at the processing stage of FIG. 1, ratherthan to actual conductively-doped regions.

A plurality of electrically insulative materials 17, 19, 21, 23 and 25are stacked over base 12, and such can be considered supportingmaterials in that they support conductive material containers (discussedbelow). The insulative materials 17 and 19 can be oxide-containingmaterials, and in particular aspects can comprise, consist essentiallyof, or consist of silicon dioxide (SiO₂) or doped silicon oxide (withexemplary doped silicon oxide being, for example, borophosphosilicateglass, BPSG, and phosphosilicate glass, PSG). Materials 17 and 19 can bereferred to as sacrificial oxides in some aspects of the invention.

The insulative materials 21, 23 and 25 can comprise, consist essentiallyof, or consist of silicon nitride; and can have exemplary thicknesses offrom about 100 Å to about 3000 Å. In some aspects, the layers ofmaterials 21, 23 and 25 can be referred to as nitride-containing layers.In other aspects, at least one of the materials 21, 23 and 25 cancomprise a composition other than silicon nitride. For instance, FIGS.23-25 (discussed below) illustrate an aspect of the invention in whichmaterial 23 is replaced with a composition (such as polysilicon) whichis selectively etchable relative to silicon nitride of layer 25.

In the aspect of the invention of FIG. 1, the insulative materials cancorrespond to, in ascending order from base 12, a firstnitride-containing layer of material 21, a first oxide-containingmaterial 17, a second nitride-containing layer of material 23, a secondoxide-containing material 19, and a third nitride-containing layer ofmaterial 25. It is to be understood that the stack can comprise othercombinations of layers besides those shown, and can, for example,comprise less than the three shown nitride-containing layers or morethan the three shown nitride-containing layers, and/or can comprise lessthan the two shown oxide-containing layers or more than the two shownoxide-containing layers

A plurality of openings 22, 24, 26 and 28 extend through materials 17,19, 21, 23 and 25 to the nodes 14, 16, 18 and 20, respectively. Aconductive material 30 extends across an upper surface of material 25,and within openings 22, 24, 26 and 28. Material 30 can comprise one ormore electrically conductive compositions. For example, material 30 caninclude various metals (for instance, Ti, W, and Ru), metal-containingcompositions (for instance, metal nitride, conductive metal oxide,etc.), and/or conductively doped semiconductor material (for instance,conductively-doped polysilicon). In some aspects material 30 cancomprise, consist essentially of, or consist of one or more of titaniumnitride, tantalum nitride, aluminum nitride and hafnium nitride.Typically, material 30 will consist essentially of, or consist oftitanium nitride. Material 30 have a thickness of from about 50angstroms to about 600 angstroms. Although material 30 is shown as beinghomogeneous in composition, it is to be understood that the material cancomprise layers of differing composition. Material 30 can be directlyagainst nodes 14, 16, 18 and 20, as shown; or can join to the nodesthrough electrically conductive layers, for instance metal silicide,and/or pedestals.

A patterned masking material 32 is provided over material 30. Themasking material can comprise any suitable composition, and typicallywill correspond to a photoresist. A plurality of gaps 34, 36, and 38extend through the patterned masking material.

Referring to FIG. 2, the gaps 34, 36 and 38 are extended throughmaterials 25 and 30, and masking material 32 (FIG. 1) is removed. Theextension of gaps 34, 36 and 38 through materials 25 and 30 exposesoxide-containing material 19.

The gaps 34, 36 and 38 subdivide the remaining material 30 into aplurality of separate upwardly-opening containers 40, 42, 44 and 46.Each of the containers is in electrical connection with one of theconductive nodes 14, 16, 18 and 20. The upwardly-extending openingswithin the containers have depths 45 (labeled for one of the openings)and widths 47 (labeled for another of the openings). The widths extendcross-sectionally across the openings, and are shown to extend laterallyrelative to the vertically-extending openings. The depths can be, forexample, at least about one micron (in some aspects, at least about fivemicrons), and the maximum cross-sectional widths (which can also beconsidered maximum cross-sectional lateral dimensions of the openings insome aspects of the invention) will typically be less than or equal toabout 4000 angstroms. In particular aspects, the maximum cross-sectionalwidths can be less than equal to about 2000 angstroms, or even less thanor equal to about 1000 angstroms.

In the shown aspect of the invention, silicon nitride-containing layer21 is in direct contact with an uppermost surface of semiconductor base12, and in some aspects such silicon nitride-containing layer can be indirect contact with monocrystalline silicon of the semiconductor base.Silicon nitride-containing layer 21 has an uppermost surface 27 that isapproximately coextensive with bottommost surfaces of containers 40, 42,44 and 46, and which accordingly can be at least about one micronbeneath uppermost surfaces of the containers, and in some aspects can beat least about five microns beneath the uppermost surfaces of thecontainers. The silicon nitride-containing layer 23 can be at leastabout one-half micron beneath the uppermost surfaces of the containers(or in other words, can have an uppermost surface that is at least aboutone-half micron beneath the uppermost surfaces of the containers; and insome aspects can be at least about one micron beneath the uppermostsurfaces of the containers).

The containers 40, 42, 44 and 46 are shown to comprise shelves 56, 58,60 and 62, respectively, which extend laterally outwardly overunderlying materials 17, 19, 21, 23 and 25. Although each containerappears to have a pair of shelves in the cross-sectional view of FIG. 2,it is to be understood that the containers would extend around the shownopenings in top view so that the apparent paired shelves on either sideof an opening in FIG. 2 are actually two sides of a single shelf thatextends entirely around the opening. In some aspects (discussed below),the shelves of material 30 can be removed by planarization (for example,CMP) prior to subsequent processing.

Referring to FIG. 3, oxide-containing material 19 (FIG. 2) is removedwith an isotropic (wet) etch to expose nitride-containing material 23within gaps 34, 36 and 38.

Referring to FIG. 4, silicon nitride-containing material 23 is subjectedto an anisotropic etch which transfers the pattern of gaps 34, 36 and 38into the material 23. Specifically, portions of the siliconnitride-containing material 23 exposed through gaps 34, 36 and 38 areremoved with a highly directional etch.

The etch is somewhat selective for silicon nitride relative toconductive material 30 (which is typically metal nitride), in that theetch removes exposed silicon nitride while not removing the majority ofmaterial 30 from within the various containers, even though material 30is also exposed to the etch. In particular aspects of the invention, theetch can utilize Cl₂, and specifically can utilize a mixture of Cl₂ andhelium in a ratio of 7:180 (Cl₂:He). The ratio of Cl₂ to He is a volumeratio determined by the relative flow rates of Cl₂ and He into areaction chamber in which the etch is conducted. The etch can beconducted with a temperature within the reaction chamber of from about1° C. to about 100° C., and with a pressure within the reaction chamberof from about 0.1 milliTorr to about 100 milliTorr. The base 12 willtypically be biased within the chamber, with such bias being from about50 watts to at least about 150 watts; and in some aspects being greaterthan or equal to about 150 watts; with exemplary bias being from about50 watts to about 600 watts. Higher bias will tend to increasedirectionality of the etch, and to also increase the selectivity of theetch for silicon nitride relative to material 30.

In exemplary aspects, silicon nitride-containing material 23 can have athickness of from about 600 Å to about 3000 Å, and the etch can beconducted for a time of from about 10 seconds to about 50 seconds tocompletely etch through such silicon nitride-containing material.

The shelves 56, 58, 60 and 62 (FIG. 3) of conductive material 30 areshown removed at the processing stage of FIG. 4. Such can beaccomplished by CMP of material 30 from over material 25, and/or byremoval of the shelves with the etching conditions used to punch throughnitride-containing material 23. Notably, although the etching conditionsused to punch through nitride-containing material 23 may remove theupper shelves of conductive material 30, the etching conditionspreferably do not appreciably penetrate into the conductive containers40, 42, 44 and 46. Thus, such etching conditions preferably do notappreciably remove layer 30 from within the container openings.

The selectivity of the FIG. 4 etch for silicon nitride-containingmaterial 23 relative to the conductive material 30 within the containersis believed to be due, at least in part, to the geometry of thecontainers. Specifically, by utilizing containers having a relativelyhigh aspect ratio, reactive etchant suitable for etching material 30 issubstantially precluded from reaching the material 30 at any significantdepth within the container openings. Yet, reactive etchant suitable foretching silicon nitride can reach entirely to, and through, the siliconnitride-containing material 23.

The reactive etchant suitable for etching silicon nitride may be adifferent species than the reactive etchant suitable for etchingmaterial 30 under the reaction conditions discussed above forutilization in exemplary aspects the present invention, so that siliconnitride can be etched in high aspect ratio openings that would beunsuitable for etching of material 30. Alternatively, the reactiveetchant suitable for etching silicon nitride may be the same as thatutilized for etching material 30, so that the geometrical constraintsare the same for removal of material 30 and silicon nitride. Regardless,methodology of the present invention can advantageously remove siliconnitride from between high aspect ratio container openings while notremoving conductive material (typically metal nitride) of the containersfrom the depths of the containers.

Referring to FIG. 5, oxide-containing material 17 (FIG. 4) is removedthrough the openings in material 23 with an isotropic etch. Such etch ispreferable selective for oxide relative to nitride, and can, forexample, be a wet etch utilizing one or more fluorine-containingcompositions.

Referring to FIG. 6, containers 40, 42, 44 and 46 can be incorporatedinto a plurality of capacitors 70, 72, 74 and 76, respectively.Specifically, electrically insulative capacitor dielectric material 64and electrically conductive capacitor plate material 66 are formed overand around containers 40, 42, 44 and 46, to form the capacitors 70, 72,74 and 76. The capacitor dielectric material can comprise any suitablecomposition or combination of compositions, including, for example,silicon dioxide, silicon nitride, and/or various high-k materials. Also,the capacitor plate material can comprise any suitable composition orcombination of compositions, including, for example, various metals,metal compositions, and/or conductively-doped semiconductor material.

In some aspects, the conductively-doped regions 14, 16, 18 and 20 cancorrespond to source/drain regions of transistors comprising transistorgates 78, 80, 82 and 84 (schematically illustrated in FIG. 6). As isknown to persons of ordinary skill in the art, the combination of acapacitor with a transistor forms a DRAM (dynamic random access memory)unit cell. Thus, the capacitors 70, 72, 74 and 76 can be incorporatedinto a DRAM array.

FIG. 7 shows another arrangement of capacitors that can be formed inaccordance with the above-discussed aspects of the invention. Thevarious materials and structures of FIG. 7 are labeled identically tothose of FIG. 6. The construction of FIG. 7 is similar to that of FIG.6, except that some regions of the nitride-containing material 23 and 25are not punched through so that such regions can correspond to straps(or supports) extending between and supporting containers of thecapacitors. Persons of ordinary skill in the art will recognize that theconstruction of FIG. 7 is a typical construction resulting from latticeapplications.

FIG. 8 shows semiconductor construction 10 at a preliminary processingstage of another aspect of the present invention, with such processingstage being analogous to that described above with reference to FIG. 1.The construction comprises the substrate 12, conductive material 30 andinsulative materials 17, 19, 21, 23 and 25 discussed above.Additionally, the construction comprises the patterned masking material32 discussed above.

The construction of FIG. 8 differs from that of FIG. 1 in thatsacrificial material 86 is provided across material 30 and withinupwardly-extending openings 22, 24, 26 and 28 at the processing stage ofFIG. 8. In some aspects, sacrificial material 86 can comprise silicon,and the sacrificial material can, for example, comprise, consistessentially of, or consist of polysilicon, or silicon dioxide.

FIG. 9, shows construction 10 at a processing stage subsequent to thatof FIG. 8, and analogous to that of FIG. 2; and specifically showsmaterial 30 patterned into a plurality of separate containers 40, 42, 44and 46, and shows material 25 punched through. However, unlike FIG. 2,the sacrificial material 86 is exposed together with insulative material19 at the processing stage of FIG. 8. In subsequent processing, material19 will be removed, analogously to the removal discussed above withreference to FIG. 3. It can be desired that the material 86 be resistantto the conditions utilized during such removal so that the material 86remains. In such applications, material 86 can comprise, for example,various polysilicon and/or insulative nitrides. Alternatively,sacrificial material 86 can consist of silicon dioxide, and can beremoved during the removal of material 19.

FIG. 10 shows construction 10 at a processing stage subsequent to thatof FIG. 9, and analogous to that of FIG. 3; and specifically shows theconstruction after material 19 (FIG. 9) has been removed with anisotropic etch.

FIG. 11 shows construction 10 at a processing stage subsequent to thatof FIG. 10, and analogous to that of FIG. 4; and specifically shows theconstruction after material 23 has been punched through with ananisotropic etch.

FIG. 12 shows construction 10 at a processing stage subsequent to thatof FIG. 11, and analogous to that of FIG. 5; and specifically shows theconstruction after material 17 (FIG. 11) has been removed with anisotropic etch; and after removal of material 86. Sacrificial material86 can be removed after the isotropic etch of material 17. Ifsacrificial material 86 consists of polysilicon, it can be selectivelyremoved relative to materials 30, 21, 23 and 25 with an isotropic wetetch utilizing TMAH. The construction of FIG. 12 can subsequently beprocessed to incorporate the containers 40, 42, 44 and 46 into aplurality of capacitors (analogously to the processing described abovewith reference to FIG. 6).

FIGS. 13-17 illustrate another aspect of the invention. Referring toFIG. 13, construction 10 is shown at a processing stage in which gaps34, 36 and 38 extend through uppermost nitride-containing material 25.Conductive material 30 is within openings 22, 24, 26, and 28 ascontainers 40, 42, 44 and 46, but is not over uppermostnitride-containing material 25. The processing stage of FIG. 13 can besubsequent to that of FIG. 2 if planarization is used to remove material30 from over material 25.

Referring to FIG. 14, construction 10 is shown at a processing stageafter material 19 (FIG. 13) has been removed through gaps 34, 36 and 38with an isotropic etch. Such exposes nitride-containing material 23.

Referring to FIG. 15, a protective material 90 is formed over uppermostnitride-containing material 25 to protect such material during asubsequent etch of underlying nitride-containing material 23. Protectivematerial 90 can be any suitable composition or combination ofcompositions. In particular aspects, material 90 will comprise, consistessentially of, or consist of silicon dioxide, and will be formed underconditions having very low step coverage. In other words, the silicondioxide will be formed under conditions in which the silicon dioxidecovers uppermost surfaces, but does not penetrate through gaps 34, 36 or38, and does not penetrate to a significant depth within containers 40,42, 44 and 46.

FIG. 16 shows construction 10 at a processing stage after punch throughof material 23 with an anisotropic etch. The protective material 90functions as a mask during the etching of material 23. Specifically,protective 90 narrows gaps 32, 34 and 36, and the dimensions of thenarrowed gaps are approximately transferred through material 23 duringthe anisotropic etch. The etch of material 23 can utilize the sameconditions discussed above with reference to FIG. 4 for etching throughmaterial 23.

Referring to FIG. 17, oxide-containing material 17 (FIG. 16) is removedwith an isotropic etch. If material 90 (FIG. 16) comprises oxide, suchcan be simultaneously removed with the same etch used to remove material17 (as shown). The construction of FIG. 17 can be subsequently processedto incorporate the containers 40, 42, 44 and 46 into a plurality ofcapacitors (similar to the processing described above with reference toFIG. 6).

FIGS. 18 and 19 illustrate another aspect of the invention. FIG. 18shows construction 10 at a preliminary processing stage corresponding tothe processing stage of FIG. 2.

FIG. 19 shows the construction 10 at a processing stage similar to thatof FIG. 5, and specifically shows the construction after it has beensubjected to etches of the types described above for selectivelyremoving silicon nitride relative to conductive material 30, and forremoving oxide-containing materials 17 and 19. Such etches have extendedgaps 34, 36 and 38 through the silicon nitride-containing materials 23and 25. In contrast to the aspect of FIG. 5, the aspect of FIG. 19 showsonly portions of the conductive material shelves removed from upperportions of the containers during the etching of the siliconnitride-containing materials. In other words, shelves 56, 58, 60 and 62are reduced in thickness during such etches, but not entirely removed.The amount, if any, of material 30 remaining as the shelves 56, 58, 60and 62 after the etching through the silicon nitride-containingmaterials can depend on the relative thicknesses of material 30 andsilicon nitride materials 23 and 25; the duration of the etches; and thechemical selectivity (as opposed to geometrical selectivity) for siliconnitride-containing material relative to conductive material 30 that isachieved by the etching conditions.

FIGS. 20-22 illustrate another aspect of the invention. Referring toFIG. 20, such shows construction 10 at a processing stage subsequent tothat of FIG. 2. A protective material 63 is over uppernitride-containing layer 25. The protective layer can comprise anysuitable composition or combination of compositions, including, forexample, photoresist and/or other masking materials. An anisotropic etchhas been utilized to etch through oxide-containing material 19. Suchanisotropic etch can utilize any suitable anisotropic etchingconditions, and typically will be a so-called dry etch.

Referring to FIG. 21, protective material 63 (FIG. 20) is removed, andsilicon nitride-containing material 23 is subjected to an anisotropicetch which transfers the pattern of gaps 34, 36 and 38 into the material23. Such exposes oxide-containing material 17 through the gaps punchedthrough material 23.

Referring to FIG. 22, oxide-containing material 17 (FIG. 21) is removedthrough the openings in material 23 with an isotropic etch, analogouslyto the processing discussed above with reference to FIG. 5. Theisotropic etch also removes remaining portions of oxide-containingmaterial 19 so that the construction of FIG. 22 is identical to that ofFIG. 5.

FIGS. 23-25 illustrate another aspect of the invention. Referring toFIG. 23, such shows a construction 100 at a processing stage analogousto that of FIG. 3. However, in contrast to the aspect of FIG. 3, theaspect of FIG. 23 comprises no protective material over uppernitride-containing material 25, and shows a material 102 in place of thecentral nitride-containing material 23 (FIG. 3). The material 102 ispreferably a composition, or combination of compositions, which can beselectively etched relative to nitride-containing material 25; and alsois electrically insulative. In particular aspects, material 102 cancomprise, consist essentially of, or consist of silicon carbide orsilicon-based films with slower etch rates than materials 17 and 19under the conditions utilized to remove materials 17 and 19. The layerof material 102 can be referred to as a support layer, in that it formsa support between adjacent containers (40, 42, 44 and 46) of material30.

Referring to FIG. 24, material 102 is subjected to an anisotropic etchwhich transfers the pattern of gaps 34, 36 and 38 into the material 102.Such exposes oxide-containing material 17 through the gaps punchedthrough material 102.

Referring to FIG. 25, oxide-containing material 17 is removed throughthe openings in material 102 with an isotropic etch, analogously to theprocessing discussed above with reference to FIG. 5. The structure ofFIG. 25 can subsequently be utilized to form a number of capacitors withprocessing analogous to that discussed above with reference to FIG. 6.

Memory cells and other structures formed in accordance with methodologyof the present invention can be incorporated into various electronicsystems.

FIG. 26 illustrates generally, by way of example but not by way oflimitation, an embodiment of a computer system 400 according to anaspect of the present invention. Computer system 400 includes a monitor401 or other communication output device, a keyboard 402 or othercommunication input device, and a motherboard 404. Motherboard 404 cancarry a microprocessor 406 or other data processing unit, and at leastone memory device 408. Memory device 408 can comprise various aspects ofthe invention described above. Memory device 408 can comprise an arrayof memory cells, and such array can be coupled with addressing circuitryfor accessing individual memory cells in the array. Further, the memorycell array can be coupled to a read circuit for reading data from thememory cells. The addressing and read circuitry can be utilized forconveying information between memory device 408 and processor 406. Suchis illustrated in the block diagram of the motherboard 404 shown in FIG.27. In such block diagram, the addressing circuitry is illustrated as410 and the read circuitry is illustrated as 412. Various components ofcomputer system 400, including processor 406, can comprise one or moreof the memory constructions described previously in this disclosure.

Processor device 406 can correspond to a processor module, andassociated memory utilized with the module can comprise teachings of thepresent invention.

Memory device 408 can correspond to a memory module. For example, singlein-line memory modules (SIMMs) and dual in-line memory modules (DIMMs)may be used in the implementation which utilize the teachings of thepresent invention. The memory device can be incorporated into any of avariety of designs which provide different methods of reading from andwriting to memory cells of the device. One such method is the page modeoperation. Page mode operations in a DRAM are defined by the method ofaccessing a row of a memory cell arrays and randomly accessing differentcolumns of the array. Data stored at the row and column intersection canbe read and output while that column is accessed.

An alternate type of device is the extended data output (EDO) memorywhich allows data stored at a memory array address to be available asoutput after the addressed column has been closed. This memory canincrease some communication speeds by allowing shorter access signalswithout reducing the time in which memory output data is available on amemory bus. Other alternative types of devices include SDRAM, DDR SDRAM,SLDRAM, VRAM and Direct RDRAM, as well as others such as SRAM or Flashmemories.

Memory device 408 can comprise memory formed in accordance with one ormore aspects of the present invention.

FIG. 28 illustrates a simplified block diagram of a high-levelorganization of various embodiments of an exemplary electronic system700 of the present invention. System 700 can correspond to, for example,a computer system, a process control system, or any other system thatemploys a processor and associated memory. Electronic system 700 hasfunctional elements, including a processor or arithmetic/logic unit(ALU) 702, a control unit 704, a memory device unit 706 and aninput/output (I/O) device 708. Generally, electronic system 700 willhave a native set of instructions that specify operations to beperformed on data by the processor 702 and other interactions betweenthe processor 702, the memory device unit 706 and the I/O devices 708.The control unit 704 coordinates all operations of the processor 702,the memory device 706 and the I/O devices 708 by continuously cyclingthrough a set of operations that cause instructions to be fetched fromthe memory device 706 and executed. In various embodiments, the memorydevice 706 includes, but is not limited to, random access memory (RAM)devices, read-only memory (ROM) devices, and peripheral devices such asa floppy disk drive and a compact disk CD-ROM drive. One of ordinaryskill in the art will understand, upon reading and comprehending thisdisclosure, that any of the illustrated electrical components arecapable of being fabricated to include memory constructions inaccordance with various aspects of the present invention.

FIG. 29 is a simplified block diagram of a high-level organization ofvarious embodiments of an exemplary electronic system 800. The system800 includes a memory device 802 that has an array of memory cells 804,address decoder 806, row access circuitry 808, column access circuitry810, read/write control circuitry 812 for controlling operations, andinput/output circuitry 814. The memory device 802 further includes powercircuitry 816, and sensors 820, such as current sensors for determiningwhether a memory cell is in a low-threshold conducting state or in ahigh-threshold non-conducting state. The illustrated power circuitry 816includes power supply circuitry 880, circuitry 882 for providing areference voltage, circuitry 884 for providing the first wordline withpulses, circuitry 886 for providing the second wordline with pulses, andcircuitry 888 for providing the bitline with pulses. The system 800 alsoincludes a processor 822, or memory controller for memory accessing.

The memory device 802 receives control signals from the processor 822over wiring or metallization lines. The memory device 802 is used tostore data which is accessed via I/O lines. It will be appreciated bythose skilled in the art that additional circuitry and control signalscan be provided, and that the memory device 802 has been simplified tohelp focus on the invention. At least one of the processor 822 or memorydevice 802 can include a memory construction of the type describedpreviously in this disclosure.

The various illustrated systems of this disclosure are intended toprovide a general understanding of various applications for thecircuitry and structures of the present invention, and are not intendedto serve as a complete description of all the elements and features ofan electronic system using memory cells in accordance with aspects ofthe present invention. One of the ordinary skill in the art willunderstand that the various electronic systems can be fabricated insingle-package processing units, or even on a single semiconductor chip,in order to reduce the communication time between the processor and thememory device(s).

Applications for memory cells can include electronic systems for use inmemory modules, device drivers, power modules, communication modems,processor modules, and application-specific modules, and may includemultilayer, multichip modules. Such circuitry can further be asubcomponent of a variety of electronic systems, such as a clock, atelevision, a cell phone, a personal computer, an automobile, anindustrial control system, an aircraft, and others.

In compliance with the statute, the invention has been described inlanguage more or less specific as to structural and methodical features.It is to be understood, however, that the invention is not limited tothe specific features shown and described, since the means hereindisclosed comprise preferred forms of putting the invention into effect.The invention is, therefore, claimed in any of its forms ormodifications within the proper scope of the appended claimsappropriately interpreted in accordance with the doctrine ofequivalents.

The invention claimed is:
 1. A method for selectively etching siliconnitride relative to conductive material, comprising: forming the siliconnitride over a semiconductor substrate; forming the conductive materialas one or more containers over the semiconductor substrate; with saidone or more containers having one or more openings with depths andwidths, and with said one or more openings having maximumcross-sectional width dimensions of less than or equal to about 4000 Å;exposing the conductive material of the one or more conductive materialcontainers and exposing at least some of the silicon nitride to an etchutilizing chlorine to remove the exposed silicon nitride while notremoving at least the majority of the conductive material from the oneor more containers.
 2. The method of claim 1 wherein said maximumcross-sectional width dimensions are less than or equal to about 2000 Å.3. The method of claim 1 wherein said maximum cross-sectional widthdimensions are less than or equal to about 1000 Å.
 4. The method ofclaim 1 wherein the conductive material comprises metal.
 5. The methodof claim 1 wherein the conductive material comprises conductive metaloxide.
 6. The method of claim 1 wherein the conductive materialcomprises conductively-doped semiconductor material.
 7. The method ofclaim 1 wherein the conductive material consists of metal nitride. 8.The method of claim 1 wherein the conductive material comprises one ormore of titanium nitride, tantalum nitride, aluminum nitride and hafniumnitride.
 9. The method of claim 1 wherein the conductive materialconsists of titanium nitride.
 10. The method of claim 1 wherein the etchis conducted in a reaction chamber, and utilizes a mixture of Cl₂ withHe in a ratio of 7:180 (Cl₂:He), as determined by relative flow rates ofthe Cl₂ and He into the chamber; and wherein the conductive material andsilicon nitride are supported by a semiconductor substrate that isbiased to at least about 25 watts during the etch.
 11. The method ofclaim 10 wherein the conductive material consists of metal nitride. 12.The method of claim 1 wherein the conductive material comprises Ti, W orRu.
 13. A method for selectively etching silicon nitride relative toconductive material, comprising: forming a construction having theconductive material as a plurality of upwardly-extending containers thathave openings with maximum cross-sectional lateral dimensions of lessthan or equal to about 4000 Å, and having the silicon nitride extendingbetween at least some of the containers; and exposing the conductivematerial of the containers and at least some of the silicon nitride toan etch utilizing Cl₂ to remove the exposed silicon nitride while notremoving at least the majority of the conductive material from thecontainers.
 14. The method of claim 13 wherein the maximumcross-sectional lateral dimensions of the openings are less than orequal to about 2000 Å.
 15. The method of claim 13 wherein the maximumcross-sectional lateral dimensions of the openings are less than orequal to about 1000 Å.
 16. The method of claim 13 wherein the conductivematerial comprises metal.
 17. The method of claim 13 wherein theconductive material comprises conductive metal oxide.
 18. The method ofclaim 13 wherein the conductive material comprises conductively-dopedsemiconductor material.
 19. The method of claim 13 wherein theconductive material comprises one or more of titanium nitride, tantalumnitride, aluminum nitride and hafnium nitride.
 20. The method of claim13 wherein the conductive material consists of titanium nitride.
 21. Amethod for selectively etching silicon nitride relative to conductivematerial, comprising: forming a construction having the conductivematerial as a plurality of upwardly-extending containers that haveopenings with maximum cross-sectional lateral dimensions of less than orequal to about 4000 Å, and having the silicon nitride extending betweenat least some of the containers; exposing the conductive materialcontainers and at least some of the silicon nitride to an etch utilizingCl₂ to remove the exposed silicon nitride while not removing at leastthe majority of the conductive material from the containers; and whereinthe etch is conducted in a reaction chamber, and utilizes a mixture ofthe Cl₂ with He in a ratio of 7:180 (Cl₂:He), as determined by relativeflow rates of the Cl₂ and He into the chamber; and wherein the metalnitride and silicon nitride are supported by a semiconductor substratethat is biased to at least about 25 watts during the etch.